<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="https://unpkg.com/vue@3/dist/vue.global.js"></script>
</head>
<body>
    <div id="app">
        <button @click="decrement">-</button><br>
        <input type="number" v-model="counter"><br>
        <button @click="increment">+</button>
    </div>
    <script>
        const obj = {
            data(){
                return{
                    counter:0
                }
            },
            methods:{
                increment(){
                    this.counter++
                },
                decrement(){
                    if(this.counter>1){
                        this.counter--
                    }
                },
            }
        };
        const app = Vue.createApp(obj).mount('#app');
    </script>
</body>
</html>